Method of manufacturing optical film

ABSTRACT

To provide a method of manufacturing an optical film formed on a plastic substrate. There is provided a method of manufacturing an optical film including the steps of laminating a separation layer and an optical filter on a first substrate, separating the optical filter from the first substrate, attaching the optical filter to a second substrate. Since the optical film manufactured according to the invention has flexibility, it can be provided on a portion or a display device having a curved surface. Further, the optical film is not processed at high temperatures, and hence, an optical film having high yield with high reliability can be formed. Furthermore, an optical film having an excellent impact resistance property can be formed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/281,551, filed Oct. 26, 2011, now allowed, which is a continuation ofU.S. application Ser. No. 10/595,310, filed Apr. 6, 2006, now U.S. Pat.No. 8,048,251, which is a U.S. National Phase of International PatentApplication No. PCT/JP2004/016180, filed Oct. 25, 2004, which claims thebenefit of a foreign priority application filed in Japan as Serial No.2003-367326 on Oct. 28, 2003, all of which are incorporated byreference.

DESCRIPTION Technical Field

The present invention relates to a method of manufacturing an opticalfilm formed over a plastic substrate.

BACKGROUND ART

In recent years, a technique of forming a thin film transistor (TFT)using a semiconductor thin film (with a thickness of approximately fromseveral nm to several hundreds nm), which is formed over a substratewith an insulated surface, has been attracting attention. The thin filmtransistor has been widely applied in various electronic devices such asan IC and an electronic apparatus. In particular, development related tothe thin film transistor as a switching element for a liquid crystalpanel and a light emitting display panel has been hurried.

With respect to a liquid crystal display panel, a liquid crystalmaterial is sandwiched between an element substrate and an opposingsubstrate. Here, TFTs using amorphous silicon or polysilicon assemiconductors are arranged in matrix, and pixel electrodes, sourcewirings and gate wirings connecting to each TFT are formed over theelement substrate respectively. The opposing substrate having anopposing electrode is placed opposite to the element substrate. Further,a color filter for color display is formed over the element substrate orthe opposing substrate. Polarizing plates are then arranged over theelement substrate and the opposing substrate as optical shutters,respectively, to display color images.

The color filter of the liquid crystal display device has colored layersconsisting of R (red), G (green), B (blue), and a light shielding mask(black matrix) covering gaps between pixels, and extracts red light,green light, and blue light by transmitting light therethrough. A lightshielding mask for the color filter is generally made from a metal filmor an organic film containing a black pigment. The color filter isarranged at a position corresponding to the pixels, thereby beingcapable of changing the colors of light to be extracted for each pixel.Note that, the position corresponding to the pixels indicates a positionthat accords with a pixel electrode.

With respect to a light emitting display device, there are a colorizingmethod by arranging light emitting elements that emit red light, greenlight, or blue light in matrix; a colorizing method by utilizing a colorfilter with use of a light emitting element that emits white light; andthe like. The colorizing method by utilizing the color filter with useof the light emitting element that emits white color is similar to acolorizing method for a liquid crystal display device using a colorfilter in principle (see patent document 1).

[Patent document 1]: Japanese Patent Application Laid-Open No.2001-217072

DISCLOSURE OF INVENTION

Conventionally, a color filter used for a liquid crystal display devicehas been formed over a glass substrate. Therefore, there has been aproblem in which the color filter formed over the glass substrate andthe liquid crystal display device using the color filter have poorimpact resistance properties and tend to be cracked easily as thethickness of the glass substrate is reduced. Consequently, it has beendifficult to fabricate a thin liquid crystal display device.

Further, since the glass substrate does not have flexibility, it hasbeen difficult to form a color film on a portion or a display devicethat has a curved surface.

Furthermore, a colored resin and a pigment dispersing resin have beengenerally used as a raw material for the color filter. In order to curethese resins, however, it is necessary to carry out a step of heating atconstant temperatures. Therefore, it has been difficult to form thecolor filter over a thermoplastic substrate.

According to the above-mentioned problems, the present inventionprovides a method of manufacturing an optical film formed over a plasticsubstrate.

According to one aspect of the invention, there is provided a method ofmanufacturing an optical film, wherein after forming a separation layerand a subject body having an optical filter over a first substrate, asecond substrate is attached to the subject body by using a firstadhesive material so that the second substrate faces the firstsubstrate, and the separation is caused between the separation layer andthe subject body.

According to another aspect of the invention, there is provided a methodof manufacturing an optical film, wherein after forming a separationlayer and a subject body having an optical filter over a firstsubstrate, a support medium is attached to the subject body by using apeelable adhesive agent so that the support medium faces the subjectbody, and the separation is caused between the separation layer and thesubject body, and after forming a second substrate on the subject bodyby using a adhesive material, the support medium and the peelableadhesive agent is separated from the optical filter.

Note, the separation layer is formed of an element selected fromtitanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W), molybdenum(Mo), copper (Cu), chromium (Cr), neodymium (Nd), iron (Fe), nickel(Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium(Os), iridium (Ir); a single layer composed of an alloy material or acompound material containing the above-mentioned elements as its mainconstituent; a lamination layer of the single layers. Further, thesubject body comprises silicon oxide, silicon oxynitride, or metaloxide.

According to another aspect of the invention, there is provided a methodof manufacturing an optical film, wherein after forming a metal layer,an insulating layer, and an optical filter over a first substrate, asecond substrate is attached to the optical filter, and the firstsubstrate is separated from the optical filter.

According to another aspect of the invention, there is provided a methodof manufacturing an optical film, wherein after forming a metal layer,an insulating layer, and an optical filter over a first substrate, theoptical filter is separated from the first substrate, and a secondsubstrate is attached to the optical filter.

In the present invention, a metal oxide layer may be formed between themetal layer and the insulating layer simultaneously with forming themetal layer and the insulating layer.

Further, the optical filter may be formed after heating the insulatinglayer to form a metal oxide layer between the metal layer and theinsulating layer.

After forming the optical filter, a metal oxide layer may be formedbetween a separation layer and the insulating layer by heating.

The insulating layer may be formed after oxidizing a surface of themetal layer to form a metal oxide film.

In a step of separating, the optical filter from the first substrate,separation is caused between the metal layer and the insulating layer,typically, between the metal layer and the metal oxide layer, or betweenthe metal oxide layer and the insulating layer, or in the metal oxidelayer by using a physical means.

The optical filter is a color filter, a color conversion filter, or ahologram color filter.

The second substrate is made from a plastic substrate. At this moment,the optical film is a film including a color filter, a color conversionfilter, or a hologram color filter.

As the second substrate, an optical film can be used. A color film, apolarizing plate, an elliptical polarizing plate composed of aretardation plate and a polarizing plate, and a light reflection filmcan be used as the optical film. At this time, the optical film havingthe optical filter exhibits plural optical functions.

It is preferable that the first substrate be a heat-resistant substrate.Typically, a glass substrate, a quartz substrate, a ceramic substrate, asilicon substrate, a metal substrate, and a stainless substrate can becited as representative examples of the substrate.

As representative examples of the metal layer, an element selected fromtitanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W), molybdenum(Mo), copper (Cu), chromium (Cr), neodymium (Nd), iron (Fe), nickel(Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium(Os), iridium (Ir); a single layer composed of an alloy material or acompound material containing the above-mentioned elements as its mainconstituent; a lamination layer of the single layers; and nitrides ofthese materials can be cited.

The insulating layer is preferably formed of oxides, for example, asingle layer of silicon oxide, silicon oxynitride, or metal oxide, or alamination layer thereof.

The metal oxide layer is a layer that is formed by oxidizing a part ofthe metal layer by a heat treatment performed at a time of forming theinsulating layer or after forming the insulating layer. Typically, themetal oxide layer is an oxide of an element selected from titanium (Ti),aluminum (Al), tantalum (Ta), tungsten (W), molybdenum (Mo), copper(Cu), chromium (Cr), neodymium (Nd), iron (Fe), nickel (Ni), cobalt(Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), andiridium (Ir).

In the invention, a display device indicates a device using a displayelement, that is, an image display device. Further, the display deviceincludes all of a module in which a light emitting element is attachedwith a connector, e.g., a FPC (flexible printed circuit), a TAB (tapeautomated bonding) tape, or a TCP (tape carrier package); a modulehaving a printed wiring board provided on an end of a TAB tape or a TCP;and a module in that a display element is directly mounted with an IC(integrated circuit) or a CPU by the COG (chip on glass) technique.

According the following embodiments, an optical filter can be formedover a plastic substrate. That is, an optical film in which an opticalfilter is formed over a plastic substrate can be manufactured. Since theoptical film manufactured according to the invention has flexibility,the optical film can be provided on a portion or a display device havinga curved surface. Further, the optical film is not subjected to atreatment at high temperatures, and hence, the optical film can beformed to have high reliability with high yield. In addition, an opticalfilm having an excellent impact resistance property can be formed.

A display device using the optical film manufactured according to theinvention has a structure in which a layer with elements formed thereinand the optical film are separately formed through different steps, andsubsequently the layer and the optical film are attached to each other.By utilizing the structure, yield of the layer with elements formedtherein, i.e., a TFT and a display element, and yield of the opticalfilm can be controlled individually, thereby suppressing the decrease ofthe yield for the display device totally.

Further, steps for manufacturing an active matrix substrate and stepsfor manufacturing an optical film can be simultaneously run, reducingthe manufacturing lead time for a display device.

Furthermore, since a plastic substrate is used, a display device havingan improved impact resistance property with reduced weight can bemanufactured.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1E are cross sectional views explaining steps ofmanufacturing an optical film according to the present invention;

FIGS. 2A to 2E are cross sectional views explaining steps ofmanufacturing an optical film according to the invention;

FIGS. 3A to 3E are cross sectional views explaining steps ofmanufacturing a substrate having a color filter according to theinvention;

FIGS. 4A to 4D are cross sectional views explaining steps ofmanufacturing a substrate having a color filter according to theinvention;

FIGS. 5A and 5B are cross sectional views explaining a light emittingdisplay device having a color filter according to the invention;

FIGS. 6A and 6B are cross sectional views explaining a liquid crystaldisplay device having a color filter according to the invention;

FIGS. 7A and 7B are top view and cross sectional view explaining a lightemitting display device panel having a color filter according to theinvention;

FIGS. 8A and 8B are top view and cross sectional view explaining aliquid crystal display device having a color filter according to theinvention;

FIGS. 9A and 9B are diagrams explaining a substrate having a colorfilter that is manufactured according to the invention; and

FIGS. 10A to 10C are diagrams explaining examples of electronicappliances.

BEST MODE FOR CARRYING OUT THE INVENTION

The best modes of the present invention will hereinafter be describedwith reference to the accompanying drawings. As will be easilyunderstood by the person skilled in the art, the present invention canbe embodied in several forms, and the embodiment modes and its detailscan be changed and modified without departing from the purpose and scopeof the present invention. Accordingly, interpretation of the presentinvention should not be limited to descriptions mentioned in embodimentmodes. Note that, portions identical to each other are denoted by samereference numerals in the accompanying drawings, and will not be furtherexplained.

Embodiment Mode 1

A method of manufacturing an optical film over a plastic substrate willbe described with reference to FIGS. 1A to 1E.

Firstly, a metal layer 102 is formed on a first substrate 101 as shownin FIG. 1A. As the first substrate, a heat-resistant material, that is,a material that can withstand a heat treatment in a step ofmanufacturing the optical film and a step of separating is used.Typically, a glass substrate, a quartz substrate, a ceramic substrate, asilicon substrate, a metal substrate, or a stainless substrate can beused.

The metal layer 102 may be formed of an element selected from titanium(Ti), aluminum (Al), tantalum (Ta), tungsten (W), molybdenum (Mo),copper (Cu), chromium (Cr), neodymium (Nd), iron (Fe), nickel (Ni),cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os),iridium (Ir); a single layer composed of an alloy material or a compoundmaterial containing the above-mentioned elements as its mainconstituent; or a lamination layer of the single layers; or nitrides ofthese, typically a single layer composed of molybdenum or an alloycontaining molybdenum or a lamination layer thereof. Note that,conditions of the subsequent separating step are changed by adjustingthe composition ratio of metal for alloy in the metal layer, or thecomposition ratio of oxygen or nitrogen contained in the metal layer,properly. Therefore, the separating step can be adapted to various kindsof processing. The film thickness of the metal layer 102 is set to 10 to200 nm, preferably, 50 to 75 nm.

Next, an oxide layer 103 is formed on the metal layer or the nitridelayer 102. At this moment, a metal oxide layer is formed between themetal layer 102 and the oxide layer 103. When separating is caused inthe subsequent step, separation will be caused inside the metal oxidelayer, in an interface between the metal oxide layer and the oxidelayer, or in an interface between the metal oxide layer and the metallayer. As for the oxide layer 103, a layer composed of silicon oxide,silicon oxynitride, or metal oxide may be formed by sputtering or plasmaCVD. It is desirable that the film thickness of the oxide layer 103 beapproximately 1 to 3 times, preferably, at least 1.5 to 2 times as largeas that of the nitride layer or the metal layer 102. A silicon oxidefilm is formed by sputtering using silicon oxide target to have athickness of from 75 to 200 nm, here.

An optical filter 104 is next formed on the oxide layer 103. Asrepresentative examples of the optical filter, a color filter, a colorconversion filter, a hologram color filter, and the like can be cited.

As shown in FIG. 1B, a second substrate 112 for fixing the opticalfilter 104 is next pasted with an adhesive material 111. As for theadhesive material, various kinds of adhesive materials including areactive curing adhesive material, a thermal curing adhesive material, alight curing adhesive material such as an ultraviolet curing adhesivematerial, an anaerobic curing adhesive material can be cited. Asrepresentative examples of these materials, an organic resin such as anepoxy resin, an acrylic resin, and a silicon resin can be cited.

The second substrate 112 is formed of a plastic substrate (a film madefrom a high molecular weight material or a resin). As representativeexamples of the plastic substrate, plastic substrates made frompolycarbonate (PC); ARTON formed of norbornene resin with a polar groupthat is manufactured by JSR corporation; polyethylene terephthalate(PET); polyether sulfone (PES); polyethylene naphthalate (PEN); nylon;polyether ether ketone (PEEK); polysulfone (PSF); polyetherimide (PEI);polyarylate (PAR); polybutylene terephthalate (PBT); polyimide; and thelike can be used. Besides, an optical film such as a polarizing plate, aretardation plate, and a light diffusing film can be used as the secondsubstrate.

Subsequently, as shown in FIG. 1C, a first support medium 121 isattached to the second substrate 112 with a peelable adhesive agent 122.At this moment, when air bubbles intrude between the second substrate112 and the peelable adhesive agent 122, cracks are easily caused in theoptical filter in the subsequent separating step. In order to preventcracking, the first support medium is attached thereto so as not tointrude air bubbles between the second substrate 112 and the peelableadhesive agent 122. Note that, the first support medium can be attachedat short times without intruding air bubbles therebetween by using atape mounter device and the like.

As the peelable adhesive agent 122, the followings can be cited: amaterial formed of an adhesive material that is made from an organicresin, typically, various kinds of peelable adhesives including areactive peeling adhesive, a thermal peeling adhesive, a light peelingadhesive such as an ultraviolet ray peeling adhesive, an anaerobicpeeling adhesive, and the like; or a member having adhesive layersformed of the various peelable adhesives on each surface thereof(typically, a two-sided tape, and a two-sided sheet).

It is preferable to use a substrate having higher rigidity than that ofthe second substrate, typically, a glass substrate, a quartz substrate,a metal substrate, or a ceramic substrate as the first support medium.

Furthermore, it is preferable that a substrate having higher rigiditythan that of the first and second substrates be employed as the firstsupport medium.

In the case where the surface of the optical filter 104 is uneven, aplanarizing layer may be formed on the surface of the optical filter asa buffer layer. Typically, an organic resin, an organic or an inorganicinsulating coating film, an insulating film planarized by the CMP(chemical-mechanical polishing) technique and the like, an adhesive, andthe like can be cited. Note that, the insulating film may have a singlelayer or a lamination structure. Besides, the planarizing layer may beformed by using both the insulating film and the adhesive.

In FIG. 1C, the first substrate 101 and the metal layer 102 formedthereon are referred to as a separation body 123. Meanwhile, layers fromthe oxide layer 103 to the second substrate 112 (that is, layerssandwiched between the metal layer 102 and the peelable adhesive agent122) are referred to as a subject body 124.

It is preferable that a support medium be bonded to the first substrate101 with a peelable adhesive agent so as to prevent breakage of eachsubstrate. By bonding the support medium thereto, the separating step,that will be carried out later, can be performed with a smaller force.Preferably, a substrate having higher rigidity than that of the firstsubstrate, typically, a quartz substrate, a metal substrate, and aceramic substrate are used as the support medium.

As shown in FIG. 1D, a separation body 123 is next separated from thesubject body 124 by a physical means. For example, the physical forceindicates a relatively small force such as human hands, gas pressureapplied from a nozzle, and ultrasonic waves.

As a result, separation is caused inside the metal layer 102, inside themetal oxide layer, in an interface between the metal oxide layer and theoxide layer 103, or in an interface between the metal oxide layer andthe metal layer so that the separation body 123 can be separated fromthe subject body 124 with a relatively small force.

Note that, in order to separate the separation body easily, apretreatment is preferably carried out as a previous step prior to theseparating step. Typically, a treatment for partly reducing theadhesiveness between the metal layer 102 and the oxide layer 103 isperformed. The treatment for partly reducing the adhesivenesstherebetween is the one performed by partly irradiating laser beam tothe metal layer 102 along a rim of a region to be separated, or the oneperformed by partly damaging inside or an interface of the metal layer102 by locally applying pressure along a rim of a region to be separatedfrom an external portion. Specifically, a hard needle such as a diamondpen may perpendicularly be pressed and moved while applying loadthereto. Preferably, a scriber device can be used to move the hardneedle while applying the pressure with press force in the range of from0.1 mm to 2 mm. Thus, it is important to form a portion where aseparating phenomenon is easily caused, that is, a trigger of theseparating phenomenon, prior to performing the separating step. Byperforming the pretreatment of selectively (partly) reducing theadhesiveness in advance, poor separation can be prevented, therebyimproving the yield.

As illustrated in FIG. 1E, the peelable adhesive agent 122 and the firstsupport medium 121 are next separated from the second substrate 112.

According to the above-described steps, the optical film can be formed.Namely, the optical filter 104 can be formed over the second substrate112.

Note that, the organic resin 111 that is an adhesive material isinterposed between the optical filter 104 and the second substrate 112.Further, the oxide layer 103 is formed on a surface of the opticalfilter 104; the surface is opposite to another surface of the opticalfilter 104 on which organic resin is formed.

Further, an optical film such as a polarizing plate, a retardationplate, and a light diffusing film can be used as the second substrate112. In addition, a known antireflection film can be formed on a surfaceof the second substrate or a surface of the oxide layer. By employingthe structure, an optical film having plural functions can be formed.

The optical film manufactured in the embodiment mode has flexibility,and hence, it can be provided on a portion or a display device having acurved surface. Further, the optical filter is not processed at hightemperatures, thereby achieving an optical filter having highreliability with high yield. Furthermore, the optical filter having anexcellent impact resistance property can be formed.

Embodiment Mode 2

In the present embodiment mode, a method of manufacturing an opticalfilter having a different adhesion surface between the optical filterand the second substrate from that of Embodiment Mode 1 will bedescribed with reference to FIGS. 2A to 2E.

As shown in FIG. 2A, the metal layer 102 and the oxide layer 103 aresequentially laminated over the first substrate 101, and the opticalfilter 104 is formed on the oxide layer 103 in the same manner asEmbodiment Mode 1. Note that, a metal oxide layer is formed between themetal layer and the oxide layer.

As shown in FIG. 2B, a first support medium 121 is next attached to theoptical filter 104 with the peelable adhesive agent 122. The firstsubstrate 101 and the metal layer 102 formed thereon are referred to asa separation body 211, here. Further, the oxide layer 103 and theoptical filter 104 (i.e., layers sandwiched between the metal layer 102and the peelable adhesive agent 122) are referred to as a subject body212.

Note that, it is preferable that a support medium be attached to thefirst substrate 101 with a peelable adhesive agent so as to preventbreakage of each substrate. By attaching the support medium thereto, theseparating step, that will be performed later, can be carried out with asmaller force. Preferably, the support medium may be formed of asubstrate having higher rigidity than that of the first substrate,typically, a quartz substrate, a metal substrate, and a ceramicsubstrate.

In the case where the surface of the optical filter 104 is uneven, aplanarizing layer may be formed on the surface of the optical filter. Byproviding the planarizing layer, it is possible to prevent atmosphericair from intruding between the optical filter and the peelable adhesiveagent, thereby improving the reliability of the separating step. Theplanarizing layer can be formed of a material that can be made byapplication such as an insulating coating film and an organic resin.When the planarizing layer is formed of a peelable material, typically,an adhesive, the planarizing layer can be removed later.

As shown in FIG. 2C, the separation body 211 is next separated from thesubject body 212 by a physical means. In order to separate easily, apretreatment as described in Embodiment Mode 1 is preferably carried outas a previous step prior to the separating step. According to thepretreatment, separation is caused inside the metal oxide layer, in aninterface between the metal oxide layer and the oxide layer, or in aninterface between the metal oxide layer and the metal layer, therebyseparating the separation body 211 from the subject body 212 by arelatively small force. Note that, the physical means mentioned inEmbodiment Mode 1 is adapted.

As shown in FIG. 2D, the second substrate 112 is next attached to theoxide layer 103 with the adhesive material 111. Thereafter, the peelableadhesive agent 122 and the first support medium 121 are separated fromthe optical filter 104.

According to the above-described steps, the optical film can be formed.Namely, the optical filter 104 can be formed over the second substrate112.

Note that, the organic resin 111 that is an adhesive material and theoxide layer 103 are interposed between the second substrate 112 and theoptical filter 104 that is formed in the present embodiment mode.

Alternatively, the separating step may be carried out after forming atransparent conductive film on the surface of the optical filter 104. Inaccordance with the step, the optical film having a pixel electrode canbe formed.

Also, an optical film such as a polarizing plate, a retardation plate,and a light diffusing film can be used as the second substrate 112. Inaddition, a known antireflection film can be formed on a surface of thesecond substrate or a surface of the oxide layer. By employing thestructure, an optical film having plural functions can be formed.

The optical film manufactured in the embodiment mode has flexibility,and therefore, it can be provided on a portion or a display devicehaving a curved surface. Further, the optical filter is not processed athigh temperatures, thereby achieving an optical filter having highreliability with high yield. Furthermore, an optical filter having anexcellent impact resistance property can be formed.

Embodiment Mode 3

With respect to Embodiment Mode 1 or Embodiment Mode 2, an easierseparating step in an interface between a separation body and a subjectbody will be described in the present embodiment mode.

After forming the metal layer 102 and the oxide layer 103 over the firstsubstrate 101, the resultant first substrate is heated. Thereafter, theoptical filter 104 is formed on the oxide layer. By performing thesteps, separation can be caused between the metal layer 102 and theoxide layer 103. At this moment, the first substrate can be heated attemperature ranges that can be withstood by the first substrate,typically, in a range of 100 to 600° C., preferably, 150 to 500° C.

As substitute for the step of the heat treatment, laser beam may beirradiated from the side of the first substrate 101. Further, a combinedtreatment of the laser irradiation and the heat treatment may be carriedout.

A continuous wave solid-state laser or a pulsed solid-state laser can beused here. Typically, as the continuous wave solid-state laser or thepulsed solid-state laser, one or more of the following lasers can beused: a YAG laser; a YVO₄ laser; a YLF laser; a YAIO₃ laser; a glasslaser; a ruby laser; an alexandrite laser; and a Ti:sapphire laser.Furthermore, as the other continuous wave laser or pulsed laser, one ormore of the following lasers can be used: an excimer laser; an Ar laser;and a Kr laser.

The laser beam can be irradiated to the metal layer from a side of thesubstrate, or from a side of the oxide layer, or from both sides of thesubstrate and the oxide layer.

Further, a beam shape of the laser beam may be a circular shape, atriangular shape, a square shape, a polygonal shape, an ellipticalshape, or a linear shape. The size of the laser beam may be in any sizesof microns, millimeters, and meters (that may also have a doted shape ora planer shape). Furthermore, in the above-mentioned oxidizing step, aregion to be irradiated with the laser beam may be overlapped with aregion where has been irradiated with the laser beam immediately beforethe above-mentioned region, or may not be overlapped therewith. Inaddition, it is preferable to use a laser beam having a wavelength offrom 10 nm to 1 mm, more preferably, from 100 nm to 10 μM.

The optical film manufactured in the embodiment mode can be separatedfrom the first substrate with a smaller physical force, therebyimproving yield and its reliability.

Embodiment Mode 4

With respect to Embodiment Mode 1 or Embodiment Mode 2, an easierseparating step in an interface between a separation body and a subjectbody will be described in the present embodiment mode. In the embodimentmode, a heat treatment is performed after forming an optical filter.

The metal layer 102 and the oxide layer 103 are formed over the firstsubstrate 101, the optical filter 104 is formed on the oxide layer 103,and then the resultant first substrate is heated. Thereafter, the secondsubstrate 112 is attached to the optical filter 104 with the adhesivematerial 111 in Embodiment Mode 1. On the other hand, the first supportmedium 121 is attached to the optical filter 104 by using the adhesiveagent 122 in Embodiment Mode 2.

As substitute for the above-mentioned steps, after forming the metallayer 102 and the oxide layer 103 over the first substrate 101, theresultant first substrate may be heated, and subsequently, the opticalfilter 104 may be formed on the oxide layer 103.

According to the steps, it is possible to separate the metal layer 102from the oxide layer 103 between the metal layer 102 and the oxide layer103 by a smaller physical means. At this moment, the first substrate canbe heated at temperature ranges that can be withstood by the firstsubstrate, typically, in a range of 100 to 300° C., preferably, 150 to250° C.

In addition, as substitute for the step of the heat treatment, laserbeam may be irradiated from a side of the first substrate 101 in thesame manner as Embodiment Mode 3. Alternatively, a combined treatment oflaser irradiation and heat treatment may be carried out.

The optical film manufactured in the embodiment mode can be separatedfrom the first substrate with a smaller physical force, therebyimproving yield and its reliability.

Embodiment Mode 5

A method of manufacturing an optical film through a different step offorming a metal oxide film from Embodiment Mode 1 and Embodiment Mode 2will be explained in the present embodiment mode.

A metal layer 102 is formed over the first substrate 101 in the samemanner as Embodiment Mode 1 and Embodiment Mode 2. A metal oxide layeris next formed on a surface of the metal layer 102. As the method offorming the metal oxide layer, a thermal oxidation treatment, an oxygenplasma treatment, a treatment with strong oxidizing solution such asozone water, and the like can be cited. By using any one of theabove-mentioned treatments, the surface of the metal layer 102 isprocessed to form the metal oxide layer with a thickness of from 1 to 10nm, preferably, from 2 to 5 nm. Thereafter, the oxide layer 103 and theoptical filter 104 are formed in the same manner as Embodiment Mode 1 orEmbodiment Mode 2 so that the optical film is formed.

The metal oxide layer, which is a part of the separation layer, can beformed in the present embodiment mode, thereby being capable of formingthe optical film with high yield.

Embodiment 1

An example of attaching an optical filter formed over a glass substrateto a plastic substrate will be explained according to the invention withreference to FIGS. 3A to 3E and FIGS. 4A to 4D. Although a color filteris used as a representative example of the optical filter in the presentembodiment, a color conversion filter, a hologram color filter, and thelike can be used in place of the color filter.

As shown in FIG. 3A, a separation layer is formed over a glass substrate(a first substrate 301). An AN100 is used as the glass substrate in theembodiment. A metal layer 302, i.e., a molybdenum film (with a thicknessof from 10 to 200 nm, preferably, from 50 to 75 nm) is formed on theglass substrate by sputtering. Subsequently, an oxide film 303, i.e., asilicon oxide film (with a thickness of from 10 to 400 nm, preferably,from 75 to 150 nm), is laminated thereon. Upon laminating the oxidelayer, a metal oxide film (i.e., a molybdenum oxide film) is formedbetween the metal layer 302 and the silicon oxide film 303. In thesubsequent separating step, separation is caused inside the molybdenumoxide film; in an interface between the molybdenum oxide film and thesilicon oxide film; or in an interface between the molybdenum oxide filmand the molybdenum film.

As depicted in FIG. 3B, a color filter is formed on the oxide layer 303.As a method of manufacturing the color filter, the following knownmethods can be employed: an etching method using a colored resin; acolor resist method using color resist; a dyeing method; anelectrodeposition method; a micelle electrolytic method; anelectrodeposition transfer method; a film diffusion method; an ink jetmethod (a droplet discharging method); a silver-salt coloring method;and the like.

In the present, a color filter is formed by the etching method using aphotosensitive resin in which pigments are dispersed. Firstly, aphotosensitive acrylic resin in which black pigments are dispersed isapplied on the oxide layer 303 by application. The acrylic resin isdried, baked preliminarily, and then is exposed and developed.Thereafter, the acrylic resin is heated at a temperature of 220° C. tobe cured so that a black matrix 311 with a thickness of from 0.5 to 1.5μm is formed. Subsequently, a photosensitive acrylic resin in which ared pigment is dispersed, a photosensitive acrylic resin in which agreen pigment is dispersed, and a photosensitive acrylic resin in whicha blue pigment is dispersed are applied over the substrate byapplication, respectively. Each photosensitive acrylic resin issubjected to the same steps of forming the black matrix so that a redcolored layer 312 (hereinafter, referred to as a colored layer R), agreen colored layer 313 (hereinafter, referred to as a colored layer G),and a blue colored layer 314 (hereinafter, referred to as a coloredlayer B) are formed to have thicknesses of from 1.0 to 2.5 μm,respectively. Thereafter, a protective film (not shown) is formed tocomplete a color filter 315.

In the present specification, the colored layer R represents a coloredlayer that transmits red light (having the peak wavelength in thevicinity of 650 nm) therethrough. The colored layer G represents acolored layer that transmits green light (having the peak wavelength inthe vicinity of 550 nm) therethrough. Further, the colored layer Brepresents a colored layer that transmits blue light (having the peakwavelength in the vicinity of 450 nm) therethrough.

As illustrated in FIG. 3C, a plastic substrate 322 is attached to thecolor filter 315 with an adhesive material 321. As for the adhesivematerial 321, an epoxy resin that is a light curing adhesive material isemployed. A polycarbonate film is used as the plastic substrate 322.

Subsequently, as illustrated in FIG. 3D, a pretreatment is performed tocarry out a separating treatment easily. By using a scriber device, ahard needle is moved while applying the pressure with press force in therange of from 0.1 mm to 2 mm so as to remove edges of the substrate. Atthis moment, separation is caused between the metal layer 302 and theoxide layer 303. By reducing the adhesiveness selectively (partly) inadvance in the pretreatment, poor separation can be prevented, therebyimproving the yield.

As shown in FIG. 3E, a first support medium 342 is attached to theplastic substrate 322 by using a peelable adhesive agent 341. Atwo-sided tape is used as the peelable adhesive agent 341, whereas aquartz substrate is used as the first support medium 342. By attachingthe first support medium to the plastic substrate, crack and breakage ofthe color filter can be prevented.

Next, as shown in FIG. 4A, a second support medium 352 is attached tothe first substrate 301 by using a peelable adhesive agent 351. Atwo-sided tape is used as the peelable adhesive agent, whereas a quartzsubstrate is used as the second support medium here as well as the firstsupport medium.

As shown in FIG. 4B, the first substrate 301 is next separated from thecolor filter 315. As illustrated in FIG. 3B, in a portion where issubjected to the pretreatment in order to perform the separatingtreatment easily, that is, in a region where the adhesiveness betweenthe metal layer 302 and the oxide layer 303 is partly reduced, the firstsubstrate 301 with the metal layer 302 formed thereon and the secondsupport medium 352 are separated by a physical means. The separation canbe performed by a relatively small force (for example, load with use ofa member, human hands, gas pressure applied from a nozzle, andultrasonic waves, and the like). In the present embodiment, a part of amember having a sharp end such as a wedge is inserted between the metallayer 302 and the oxide layer 303 to separate the two layers. Thus, thecolor filter 315 formed on the silicon oxide layer 303 can be separatedfrom the first substrate 301 and the metal layer 302.

Next, the first support medium 342 is separated from the plasticsubstrate 322 as illustrated in FIG. 4C. If the adhesive materialremains on the plastic substrate, the residue of the adhesive materialmight cause defects. Therefore, it is preferable that the surface of theplastic substrate 322 be washed by O₂ plasma irradiation, ultravioletray irradiation, or ozone cleaning. In addition, vacuum heating may beperformed so as to remove adsorbed moisture on the plastic substrate.

According to the above-described steps, the color filter 315 is formedon the plastic substrate 322 while sandwiching the organic material thatis the adhesive material therebetween, as shown in FIG. 4D. Note that,the oxide layer 303 is formed on the surface of the color filter. Thecolor filter 315, the oxide layer 303 formed on the surface of the colorfilter, the adhesive material (resin layer) 321, and the plasticsubstrate 322 are referred to as a substrate 361 having the colorfilter.

FIG. 9A shows a photograph of the substrate having the color filter thatis manufactured in the present embodiment. FIG. 9 B is a pattern diagramof FIG. 9A, wherein reference numeral 901 denotes a hand; 902, a plasticsubstrate; and 903, a color filter. The plastic substrate is curvedsince it has flexibility.

Note that, Embodiment Mode 2 is applicable to the present embodiment inplace of Embodiment Mode 1.

In accordance with the embodiment, a color filter can be formed on aplastic substrate. Furthermore, by forming a color filter on an opticalfilm such as a polarizing plate, a retardation plate, and a lightdiffusing film, an optical film integrated with plural functions can beformed.

The plastic substrate having the color filter manufactured according tothe present embodiment has flexibility, and hence, it can be provided ona portion or a display device having a curved surface. Further, sincethe color filter is not processed at high temperatures, the substratehaving the color filter can be manufactured so as to have highreliability with high yield. Furthermore, the substrate having the colorfilter, that comprises an excellent impact resistance property, can beformed.

Embodiment 2

In the present embodiment, an example of a light emitting display devicehaving the color filter manufactured in Embodiment 1 will be describedwith reference to FIGS. 5A and 5B.

A light emitting display device, which can emit light downward, isillustrated in FIG. 5A. In FIG. 5A, reference numeral 501 denotes alayer with elements formed therein; 361, the substrate having the colorfilter manufactured in Embodiment 1; and 500, a second substrate.

In the layer with the elements formed therein, a TFT 502 is formed as asemiconductor element over an insulating film 520. The structure of theTFT 502 is not particularly limited, and a top-gate TFT (typically, aplanar TFT) or a bottom-gate TFT (typically, an inverted stagger typeTFT) may be used. As for the elements, an organic semiconductortransistor, a diode, or an MIM element can be used as substitute for theTFT.

A first electrode made from a conductive oxide film is connected to theTFT 502 as a pixel electrode. In the present embodiment, the firstelectrode is used as an anode 503. A second electrode is opposed to thefirst substrate while sandwiching a layer containing a luminescentsubstance therebetween. The second electrode is used as a cathode 505here. The conductive oxide film used here is transparent to visiblelight. Light generated in a light emitting layer is extracted to outside(in a direction of arrows in the drawing) through the anode 503. The TFT502 and the anode 503 are provided in each of a plurality of pixels.

A light emitting layer 504 is formed so as to be in contact with theanode 503, and the cathode 505 is formed thereon. The light emittinglayer 504 corresponds to a light emitting portion of a light emittingelement, and is composed of a single layer or a lamination layer.Basically, the light emitting layer comprising a hole injecting layer, ahole transporting layer, an electron injecting layer, and an electrontransporting layer. Besides, the light emitting layer may be composed ofany known structures. As a material for the light emitting layer, eitheran organic material or an inorganic material can be used. In the case ofusing the organic compound, either a high molecular weight organicmaterial or a low molecular weight organic material may be used.

The cathode is preferably made from a material having a low workfunction, and a metal film containing an element that belongs to thegroup 1 or 2 of the periodic table may be used. Of course, any knowncathode materials can be employed.

In the present specification, the light emitting element indicates alight emitting element including an anode, a light emitting layer, and acathode. Therefore, a light emitting element 506 is composed of theanode 503, the light emitting layer 504, and the cathode 505.

Since the anode 503 has a light transmitting property while the cathode505 has a light shielding property or a light reflecting property, thelight emitting element emits light toward the anode, that is, toward theTFT (i.e., bottom emission, here). Accordingly, the substrate 361 havingthe color filter, which is formed in Embodiment 1, is attached to asurface through which light is emitted, i.e., a surface of theinsulating film 520 of the layer 501 with elements formed therein, whichis the TFT side of the layer 501 with elements formed therein, by usingan adhesive material 508.

Meanwhile, the light emitting element 506 is covered with a sealingmaterial 507, and a second substrate 500 is attached to the lightemitting element with the sealing material 507. The sealing material 507is composed of a resin, and an ultraviolet curing resin or an epoxyresin is typically used.

The second substrate 500 protects the light emitting element 506 frommoisture and oxygen, and also functions as a protective layer forprotecting the light emitting element 506 from mechanical shock.Although the second substrate 500 may be formed of any materials, it ispreferable that a plastic substrate be used so as to reduce the weightof the light emitting display device and enhance an impact resistanceproperty. A polycarbonate (PC) film is used as the plastic substrate inthe present embodiment.

Steps of manufacturing the light emitting display device as shown inFIG. 5A will be explained below.

The layer 501 with the elements formed therein that is formed by a knownmethod, is formed on a first substrate (not illustrated in the drawing).The second substrate 500 is attached to the layer 501 with the elementsformed therein by using a sealing material 507. Thereafter, the firstsubstrate is removed from the layer 501 with the elements formedtherein. As a method of removing the first substrate, a step ofseparating the first substrate, a step of polishing the first substrate,a step of melting the first substrate, and the like may properly beapplied. Note that, the first substrate may be polished thinly to use asthe second substrate. In the present embodiment, by utilizing the sametechnique as Embodiment Mode 1 or Embodiment Mode 2, a metal layer, anoxide layer, and the layer with elements formed therein are sequentiallylaminated over the first substrate. Then, separation is caused betweenthe metal layer and the oxide layer to remove the first substrate fromthe layer 501 with the elements formed therein.

Next, the substrate 361 having the color filter manufactured inEmbodiment 1 is attached to the insulating film 520 of the layer 501with the elements formed therein by using an adhesive material 508.Here, the insulating film 520 is formed on a surface through which thelight emitting element emits light, i.e., a surface of the layer 501with the elements formed, which is opposite to another surface of thelayer 501 with the elements formed therein on which the second substrate500 is formed. As representative examples of the adhesive material 508,the ultraviolet curing resin or the epoxy resin can be cited.

According to the steps above, the light emitting display device usingthe plastic substrate and the color filter formed on the plasticsubstrate (bottom emission type light emitting display device) can bemanufactured.

Next, a light emitting display device that can emit light upward isshown in FIG. 5B.

In FIG. 5B, reference numeral 501 denotes the layer with the elementsformed therein; 361, the substrate having the color filter manufacturedin Embodiment 1; and 511, the second substrate.

The TFT 502 and the light emitting element 506 are formed in the layer501 with the elements formed therein as well as FIG. 5A. With respect tothe light emitting element, an anode comprises a light shieldingproperty or a light reflecting property, whereas a cathode comprises alight transmitting property. Therefore, the light emitting element asshown in FIG. 5B emits light toward the cathode, that is, in theopposite direction of the TFT 502 (i.e., top-emission, here). The lightemitting element 506 is covered with the sealing material 507.

The substrate 361 having the color filter formed in Embodiment 1 isattached to a side through which light is emitted, i.e., a surface ofthe layer 501 with the elements formed therein, which is opposite toanother surface of the layer 501 with the elements formed therein onwhich TFT is formed by using the sealing material 507. The sealingmaterial 507 is a resin, and the ultraviolet curing resin or the epoxyresin is typically used. Note that, an adhesive material mayadditionally be provided between the sealing material 507 and thesubstrate 361 having the color filter.

Meanwhile, at a side of the TFT of the layer with the elements formedtherein, i.e., a surface of the layer with the elements formed therein,which is opposite to another surface of the layer with the elementsformed therein on which the substrate 361 having the color filter isformed, the insulating film 520 is attached to the second substrate 511by using the adhesive material 508.

Steps of manufacturing the light emitting display device shown in FIG.5B will be described below.

The layer 501 with the elements formed therein, which is formed by aknown method, is formed on a first substrate (not illustrated in thedrawing). The substrate 361 having the color filter manufactured inEmbodiment 1 is attached to the layer 501 with the elements formedtherein by using the sealing material 507. Thereafter, the firstsubstrate is removed from the layer 501 with the elements formedtherein. As a method of removing the first substrate, a step ofseparating the first substrate, a step of polishing the first substrate,a step of melting the first substrate, and the like may properly beadapted. Note that, the first substrate may be polished thinly toremain. In the present embodiment, by utilizing the same technique asEmbodiment Mode 1 or Embodiment Mode 2, a metal layer, an oxide layer,and the layer with elements formed therein are sequentially laminatedover the first substrate. Then, separation is caused between the metallayer and the oxide layer to remove the first substrate from the layer501 with the elements formed therein

Subsequently, in the layer 501 with the elements formed therein, thesecond substrate 511 is attached to the insulating film 520 of the layer501 with the elements formed therein, i.e., a surface of the layer 501with the elements formed therein, which is opposed to another surface ofthe layer 501 with the elements formed therein on which substrate 361having the color filter is formed, by using the adhesive material 508.As representative examples of the adhesive material 321, the ultravioletcuring resin or the epoxy resin can be cited.

According to the above-mentioned steps, the light emitting device usingthe plastic substrate and the color filter formed over the plasticsubstrate (top-emission type light emitting display device) can bemanufactured.

Note that, it is preferable to use colored layers of the color filterfor the light emitting display device each of which has low pigmentcontent so as to obtain a large amounts of light. Alternatively, theamount of light can be increased by making the film thickness of eachcolored layer thin. Also, when a black pigment is doped in the coloredlayers, such a defect that an observer is reflected in a cathode can beprevented by absorbing outside light entered from the outside of thelight emitting display device.

Further, an antireflection film may be provided on the surface of thesubstrate 361 having the color filter. The antireflection film is asingle layer film or a lamination film having a condition in whichreflected light is hardly caused by controlling a refractive index and afilm thickness. A known antireflection film can be used.

Further, a polarizing plate or a circular polarizing plate (including acircular polarizing film) may be used instead of the plastic substrate322.

Although examples in which the light emitting element emits light inonly one direction are shown in the embodiment, the present invention isnot limited thereto. The present invention can be applied to a lightemitting element, which can emit light in two directions (that is, alight emitting element in that both of an anode and a cathode comprisethe light transmitting properties, i.e., a dual-emission type lightemitting element). In this case, the layer with the elements formedtherein may be interposed between two substrates having color filters.

Although the present embodiment shows the light emitting element drivenby an active matrix driving method, wherein TFTs are formed in eachpixel electrode, the present embodiment is not limited thereto. A lightemitting element driven by a passive matrix driving method may be usedproperly.

In addition, a light emitting display device may be formed by using anorganic semiconductor transistor as an element provided in each pixelelectrode, and a plastic substrate as the first substrate. In this case,the step of removing the first substrate can be omitted, therebyincreasing throughput.

One feature of the light emitting display devices described in thisembodiment is that the layer with the elements formed therein and thecolor filter are formed individually in the separating steps, and thenboth are attached to each other after being completed. By taking such astructure, the yield of the layer with the elements, i.e., the TFT andthe light emitting element, formed therein, and the yield of the colorfilter can be controlled individually, which suppresses decline in theyield of the entire light emitting display device.

Furthermore, the steps of manufacturing an active matrix substrate andthe steps of manufacturing a color filter can be simultaneously run,thereby reducing manufacturing lead time of the light emitting displaydevice.

By utilizing a plastic substrate, a light emitting display device havingreduced weight with an improved impact resistance property can bemanufactured.

Embodiment 3

An example of a liquid crystal display device having the color filtermanufactured in Embodiment 1 will be explained in the presentembodiment.

In FIG. 6A, reference numeral 601 denotes a layer with elements formedtherein; 361, the substrate having the color filter manufactured inEmbodiment 1; and 500, a second substrate.

A TFT 502 as semiconductor element and a layer to be filled with aliquid crystal later are formed in the layer 601 with the elementsformed therein in the same manner as Embodiment 2. A structure of theTFT 502 is not particularly limited, and either a top-gate TFT(typically, a planar TFT) or a bottom-gate TFT (typically, a invertedstagger type TFT) may be used. As substitute for the TFT, an organicsemiconductor transistor, a diode, and an MIM element can be used as theelement.

A first electrode 602 made from a conductive oxide film is connected tothe TFT as a pixel electrode. The conductive oxide film used here istransparent to visible light, and light emitted from an externalbacklight is extracted to outside through the first electrode 602. TheTFT 502 and the first electrode 602 are provided in each of a pluralityof pixels.

An alignment film 603 is formed on the first electrode 602. An alignmentfilm that is formed by rubbing polyimide is used in the presentembodiment. Besides, an alignment film formed by the oblique depositionwith use of silicon oxide, or a photo-alignment film can be used as thealignment film.

A second electrode 606 and an alignment film 605 formed in the same stepas the alignment film 603 are formed over the second substrate 500.

The alignment film 605 formed over the second substrate 500 and thelayer 601 with the elements formed therein are attached to each otherwith a sealing material (not shown in the drawing).

A substrate 608 having a color filter is attached to a surface of aninsulating film 520 of the layer 601 with the elements formed therein byusing an adhesive material 607.

Steps of manufacturing the liquid crystal display device as shown inFIG. 6A will hereinafter be explained.

The second electrode 606 made from the conductive oxide film is formedon the second substrate 500. Thereafter, the alignment film 605 isformed on the surface of the second electrode.

The layer 601 with the elements formed therein is formed on a firstsubstrate (not shown in the drawing) by a known method. The secondsubstrate 500 is attached to the layer 601 with the elements formedtherein by using a first sealing material. In this case, the secondsubstrate is attached thereto so that the alignment film 603 formed onthe surface of the layer 601 with the elements formed therein and thealignment film 605 formed over the second substrate are faced to eachother. Further, a spacer is formed between the two substrates. The firstsealing material is mixed with filler such that the two substrates areattached to each other while maintaining an even distance therebetweenwith the spacer and the filler.

Thereafter, the first substrate is removed from the layer 601 with theelements formed therein. The known techniques as disclosed in Embodiment2 can be adapted to the step of removing the first substrate. In thisembodiment, by utilizing a same technique as Embodiment Mode 1 orEmbodiment Mode 2, a metal layer, an oxide layer, and the layer with theelements formed therein are sequentially laminated over the firstsubstrate. Then, separation is caused between the metal layer and theoxide layer to remove the first substrate from the layer 601 with theelements formed therein.

Subsequently, the substrate 361 having the color filter and theinsulating film 520 of the layer 601 with the elements formed thereinare attached to each other with the adhesive material 607.

A liquid crystal material 604 is injected between the two substrates,that is, in the layer 601 with the elements formed therein, and the twosubstrates are completely sealed with a second sealing material (notillustrated in the drawing).

According to the above-mentioned steps, the liquid crystal displaydevice using the plastic substrate and the color filter formed over theplastic substrate can be manufactured.

Next, in FIG. 6B, reference numeral 601 denotes a layer with elementsformed therein; 608, a substrate having a color filter; and 511, asecond substrate.

The second substrate 511 and an insulating film 520 of the layer 601with the elements formed therein are attached to each other with anadhesive material 607 composed of an organic resin.

The layer 601 with the elements formed therein is adhered with thesubstrate 608 having the color filter by a sealing material (notillustrated in the drawing).

The substrate 608 having the color filter is formed in accordance withEmbodiment Mode 2. Specifically, an adhesive material 610 comprisingorganic resin and an oxide layer 303 are laminated over a plasticsubstrate 322. A black matrix 311, a red colored layer 312, a greencolored layer 313, and a blue colored layer 314 are aligned on the oxidelayer and an overcoat layer for covering the layers is formed thereon soas to form the color filter. A second electrode 606 is formed over asurface of the color filter, and an alignment film 605 is formedthereon. Note that, it is possible to use a substrate having the colorfilter in which the second electrode 606 and the alignment film 605 areformed over a surface of the oxide layer 303 of the substrate 361 havingthe color filter as disclosed in Embodiment 1.

Steps of manufacturing the liquid crystal display device as shown inFIG. 6B will be described below.

The layer 601 with the elements formed therein is formed on a firstsubstrate (not shown in the drawing) by a known method. The substrate608 having the color filter is attached to the layer 601 with theelements formed therein by using a first sealing material (notillustrated in the drawing). In this case, the substrate 608 having thecolor filter is attached thereto so that the alignment film 603 formedon the surface of the layer 601 with the elements formed therein and thealignment film 605 formed on the substrate having the color filter arefaced to each other. Further, a spacer is formed between the twosubstrates. The first sealing material is mixed with filler so that thetwo substrates are attached to each other while maintaining an evendistance therebetween with the spacer and the filler.

Thereafter, the first substrate is removed from the layer 601 with theelements formed therein. The known techniques as disclosed in Embodiment2 can be applied to the step of removing the first substrate. In thisembodiment, by utilizing the same technique as Embodiment Mode 1 orEmbodiment Mode 2, a metal layer, an oxide layer, and the layer with theelements formed therein are sequentially laminated over the firstsubstrate. Then, separation is caused between the metal layer and theoxide layer to remove the first substrate from the layer 601 with theelements formed therein.

Subsequently, the second substrate 511 and the insulating film 520 ofthe layer 601 with the elements formed therein are attached to eachother with an adhesive material 607.

A liquid crystal material 604 is injected between the two substrates,that is, in the layer 601 with the elements formed therein, and the twosubstrates are completely sealed with a second sealing material (notillustrated in the drawing).

According to the above-mentioned steps, the liquid crystal displaydevice using the plastic substrate and the color filter formed over theplastic substrate can be manufactured as shown in FIG. 6B.

Note that, it is preferable that the color filter used in the liquidcrystal display device has a sharp peak wave length. Also, when a blackpigment is doped in colored layers, such a defect that an observer isreflected in a cathode can be prevented by absorbing outside lightentered from the outside of the light emitting display device.

Further, an antireflection film may be provided on each surface of thesubstrates 361 and 608 having the color filters. The antireflection filmis a single layer film or a lamination film having a condition in whichreflected light is hardly caused by controlling a refractive index and afilm thickness. A known antireflection film can be used.

Further, a polarizing plate and a circular polarizing plate (including acircular polarizing film) may be used instead of the plastic substrate322.

Although the present embodiment shows a liquid crystal element driven byan active matrix driving method, wherein TFTs are provided in each pixelelectrode, the present embodiment is not limited thereto. A liquidcrystal element driven by a passive matrix driving method can also beused, properly.

In addition, the liquid crystal display device may be formed by using anorganic semiconductor transistor as the elements formed in each pixelelectrode, and a plastic substrate as the first substrate. In this case,the step of removing the first substrate can be omitted, therebyincreasing throughput.

One feature of the liquid crystal display device described in thisembodiment is that the layer with the elements formed therein and thecolor filter are formed individually in the separating steps, and thenboth are attached to each other after being completed. By taking such astructure, the yield of the layer with the elements, i.e., the TFT andthe liquid crystal element, formed therein and the yield of the colorfilter can be controlled individually, which suppresses decline in theyield of the entire liquid crystal display device.

Furthermore, the steps of manufacturing an active matrix substrate andthe steps of manufacturing a color filter can be simultaneously run,thereby reducing manufacturing lead time of the entire liquid crystaldisplay device.

By utilizing a plastic substrate, a liquid crystal display device havingreduced weight with an improved impact resistance property can bemanufactured.

Embodiment 4

In the present embodiment, an exterior appearance of a panelcorresponding to one embodiment of a display device will be explainedwith reference to FIGS. 7A and 7B. FIG. 7A shows a top view of a panelin which a layer 501 with elements formed therein (concretely, a TFT anda light emitting element) is encapsulated between a color filter and asecond substrate by using a sealing material. FIG. 7B corresponds to across sectional view taken along a line A-A′ of FIG. 7A.

Reference numeral 1201 denoted by a doted line is a signal line drivercircuit; 1202, a pixel portion; and 1203, a scanning line driver circuitin FIG. 7A. Further, reference numeral 1204 denotes a second substrateand reference numeral 1205 denotes a first sealing material thatcontains a gap material for maintaining a gap of an enclosed space. Theinside surrounded by the sealing material 1205 is filled with a secondsealing material. As the first sealing material, an epoxy resincontaining filler with high viscosity is preferably used. As the secondsealing material, epoxy resin having high light transmitting propertywith low viscosity is preferably used. Further, it is desirable that thesealing materials 1205 and 1207 be materials that do not transmitmoisture and oxygen as much as possible.

In a connection region 1210, reference numeral 1208 denotes a connectionwiring for transmitting signals inputted in the signal line drivercircuit 1201 and the scanning line driver circuit 1203, and receives avideo signal and a clock signal from an FPC (flexible printed circuit)1209 that becomes an external input terminal.

Next, a cross sectional structure will be described referring to FIG.7B. A driver circuit and a pixel portion are formed over the firstsubstrate 322. As the substrate 361 having the color filter, a colorfilter is provided on the first substrate 322. The signal line drivercircuit 1201 as the driver circuit, and the pixel portion 1202 are shownhere. A CMOS circuit composed by combining an n-channel TFT 1223 and ap-channel 1224 is formed as the signal line driver circuit 1201.

The pixel portion 1202 is composed of a plurality of pixels including aswitching TFT 1211, a current controlling TFT 1212, and a firstelectrode (anode) 1213 made from a transparent conductive film, which iselectrically connected to a drain of the current controlling TFT 1212.

An interlayer insulating film 1220 of these TFTs 1211, 1212, 1223, and1224 may be formed of a material containing an inorganic material (suchas silicon oxide, silicon nitride, and silicon oxynitride); or anorganic material (such as polyimide, polyamide, polyimide amide,benzocyclobutene, and siloxane polymer) as its principal constituent.When siloxane polymer is used as a raw material of the interlayerinsulating film, an insulating film having a skeleton structure ofsilicon and oxygen and including hydrogen or/and alkyl group in a sidechain is formed.

The first electrode 1213 is connected to the connection electrode so asto overlap each other, and is electrically connected to a drain regionof the TFTs via the connection electrode. It is preferable that thefirst electrode 1213 have transparency and be formed of a conductivefilm having a high work function (such as ITO (indium oxide-tin oxidealloy), indium oxide-zinc oxide alloy (In₂O₃—ZnO), and zinc oxide(ZnO)).

An insulator 1214 (referred to as a bank, a partition wall, a barrier,an embankment, etc.) is formed on each end of the first electrode(anode) 1213. To improve coverage of a film formed on the insulator1214, an upper edge portion or a lower edge portion of the insulator1214 is formed to have a curved face having a radius of curvature.Further, the insulator 1214 may be covered with a protective film madefrom an aluminum nitride film, an aluminum nitride oxide film, a thinfilm containing carbon as its principal constituent, or a siliconnitride film.

An organic compound material is vapor deposited on the first electrode(anode) 1213 to form a layer 1215 containing a luminescent substanceselectively.

To remove gases contained in the substrate prior to performing the vapordeposition of the material for the layer containing the luminescentsubstance, a heat treatment at a temperature of 200 to 300° C. isdesirably carried out under a reduced pressure atmosphere or an inertatmosphere.

In order to make the layer 1215 containing the luminescent substanceemits white light, for example, white light emission can be achieved bysequentially laminating Alq₃, Alq₃ partially doped with Nile red, whichis a red light emitting pigment, p-EtTAZ, and TPD (aromatic diamine) byusing vapor deposition. Further, when an EL layer is formed byapplication using spin coating, it is preferable to bake the layer byvacuum heating after its application. For example, an aqueous solutionof poly(ethylene dioxythiophene)/poly(styrene sulfonic acid)(PEDOT/PSS), which functions as a hole injecting layer, may be appliedover the entire surface of the substrate and baked. Subsequently, asolution of polyvinyl carbazole (PVK) doped with a pigment forluminescence center (such as 1,1,4,4-tetraphenyl-1,3-butadiene (TPB),4-dicyanomethylene-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran (DCM1),Nile red, and coumarin 6), which serves as a light-emitting layer, maythen be applied over the entire surface and baked.

The layer 1215 containing the luminescent substance may be formed tohave a single layer. In this case, 1,3,4-oxadiazole derivative (PBD),which has electron transporting properties, may be dispersed inpolyvinyl carbazole (PVK), which has hole transporting properties. Inaddition, white light emission can also be, obtained by dispersing 30 wt% of PBD as an electron transporting agent and dispersing a suitableamount of four kinds of pigments (TPB, coumarin 6, DCM1, and Nile red).In addition to the above-mentioned light emitting element that emitwhite light, a light emitting element that emit red light, green light,or blue light can be manufactured by properly selecting the material ofthe layer 1215 containing the luminescent substance.

Further, triplet excited luminescent materials including metal complexesand the like may be used for the layer 1215 containing the luminescentsubstance instead of the above-mentioned singlet excited luminescentmaterials. That is, the layer 1215 containing the luminescent substancemay includes pixels emitting red light, pixels emitting green light, andpixels emitting blue light, wherein the pixels emitting red lightcontain the triplet excited luminescent material or the singlet excitedluminescent material, the pixels emitting green light contain thetriplet excited luminescent material, and the pixels emitting blue lightcontains the singlet excited luminescent material.

As a material for the second electrode (cathode) 1216, a material havinga low work function (Al, Ag, Li, Ca; alloy of these such as MgAg, MgIn,AlLi, CaF₂, and CaN) may be used.

Thus, a light emitting element 1218 composed of the first electrode(anode) 1213, the layer 1215 containing the luminescent substance, andthe second electrode (cathode) 1216 can be formed. The light emittingelement 1218 emits light in a direction of an arrow shown in FIG. 7B.The light emitting element 1218 is one of light emitting elements thatemit white light. A full color display can be performed by transmittinglight emitted from the light emitting element 1218 through the colorfilter.

Alternatively, when the light emitting element 1218 is one of lightemitting elements that emit monochromatic light of R, G; or B, threelight emitting elements having layers containing organic compounds,which emit R, and B lights respectively, are selectively used, therebyperforming a full color display. In this case, a light emitting displaydevice with high color purity can be obtained by aligning of respectivecolored layers of red, green, and blue for the color filter and thelight emitting elements for each luminescent color.

A protective layer 1217 is formed to encapsulate the light emittingelement 1218. The protective layer is composed by laminating a firstinorganic insulating film, a stress relaxation film, and a secondinorganic insulating film.

In the embodiment, the substrate 361 having the color filter is attachedto the layer 501 with the elements formed therein by the adhesivematerial 508 as shown in FIG. 5A of Embodiment 2. Note that, the colorfilter may be used as the second substrate, and the plastic substratemay be used as the first substrate as shown in FIG. 5B of Embodiment 2.

Although the scanning line driver circuit formed by using the TFTs isshown here, the prevent embodiment is not limited to the structure.Alternatively, a scanning line driver circuit and a signal line drivercircuit may be formed of transistors using a single-crystalsemiconductor, and attached.

One feature of the light emitting display device described in thisembodiment is that the layer with the elements formed therein and thecolor filter are formed individually in the separating steps, and thenboth are attached to each other after being completed. By taking such astructure, the yield of the layer with the elements, i.e., the TFT andthe light emitting element, formed therein, and the yield of the colorfilter can be individually controlled, thereby suppressing decline inthe yield of the entire light emitting display device.

Furthermore, the steps of manufacturing an active matrix substrate andthe steps of manufacturing a color filter can be simultaneously run,thereby reducing manufacturing lead time of the light emitting displaydevice.

By utilizing a plastic substrate, a light emitting display device havingreduced weight with an improved impact resistance property can bemanufactured.

Embodiment 5

In the present embodiment, an exterior appearance of a panelcorresponding to one embodiment of a display device of the inventionwill be explained with reference to FIGS. 8A and 8B. FIG. 8A shows a topview of a panel in which a layer 601 with elements formed therein(concretely, a TFT and a liquid crystal layer) is encapsulated between asubstrate 361 having a color filter and a second substrate 1204 by usinga sealing material 1205. FIG. 8B corresponds to a cross sectional viewtaken along a line A-A′ of FIG. 8A.

In FIG. 8A, reference numeral 1201 denoted by a doted line is a signalline driver circuit; 1202, a pixel portion; and 1203, a scanning linedriver circuit. Further, reference numeral 322 denotes a first substrateand reference numeral 1204 denotes a second substrate, and referencenumerals 1205 and 1207 denote a first sealing material and a secondsealing material, respectively, that contain a gap material formaintaining a gap of an enclosed space. A layer in which semiconductorelements, typically, TFTs 1223, 1224, and 1311 are formed, is attachedto the first substrate by using an adhesive material 607. The firstsubstrate 322 and the second substrate 1204, that is, the layer with theelements formed therein and the second substrate are sealed with asealing material 1205, and a liquid crystal is filled therebetween.

Next, a cross sectional structure will be described referring to FIG.8B. A driver circuit and a pixel portion are formed over the firstsubstrate 322, which includes a plurality of semiconductor elementsrepresented by the TFTs. As the substrate 361 having the color filter, acolor filter is provided on the first substrate 322. The signal linedriver circuit 1201 as a driver circuit and the pixel portion 1202 areshown here. A CMOS circuit composed by combining an n-channel TFT 1223and a p-channel TFT 1224 is formed as the signal line driver circuit1201.

The first electrode 1313 of a liquid crystal element 1315 iselectrically connected to the TFT 1311 via a wiring 1312. A secondelectrode 1316 of the liquid crystal element 1315 is formed on thesecond substrate 1204. A portion overlapped with the first electrode1313, the second electrode 1316, and the liquid crystal 1314 correspondsto the light crystal element 1315.

Reference numeral 1318 denotes a spherical spacer, which is provided forcontrolling a distance (cell gap) between the first electrode 1313 andthe second electrode 1316. A spacer that is formed by etching aninsulating film into a predetermined shape may be used instead. Variouskinds of signals and voltage supplied to the scanning line drivercircuit 1203 or the pixel portion 1202 are supplied from an FPC 1209 viaa connection wiring 1208.

In the present embodiment, the substrate 361 having the color filter isattached to the layer 601 with the elements formed therein by using anadhesive material 607 as illustrated in FIG. 6A of Embodiment 3. Notethat, the color filter may be used as the second substrate, whereas theplastic substrate may be used as the first substrate in the same manneras FIG. 6B of Embodiment 3.

Although the scanning line driver circuit formed by using the TFTs isshown here, the prevent embodiment is not limited to the structure.Alternatively, a scanning line driver circuit and a signal line drivercircuit may be formed of transistors using a single-crystalsemiconductor, and attached.

One feature of the liquid crystal display device described in thisembodiment is that the layer with the elements formed therein and thecolor filter are formed individually in the separating steps, and thenboth are attached to each other after being completed. By taking such astructure, the yield of the layer with the elements, i.e., the TFT andthe light emitting element, formed therein and the yield of the colorfilter can be individually controlled, thereby suppressing decline inthe yield of the entire liquid crystal display device.

Furthermore, the steps of manufacturing an active matrix substrate andthe steps of manufacturing a color filter can be simultaneously run,thereby reducing manufacturing lead time for the liquid crystal displaydevice.

By utilizing a plastic substrate, a liquid crystal display device havingreduced weight with an improved impact resistance property can bemanufactured.

Embodiment 6

Various kinds of electronic appliances can be manufactured byincorporating display devices obtained according to the invention.Examples of the electronic appliances include: a TV set; a video camera;a digital camera; a goggle type display (a head-mounted display); anavigation system; an audio reproduction device (such as a car audio andan audio component system); a personal laptop computer; a game machine;a portable information terminal (such as a mobile computer, a cellulartelephone, a portable game machine, and an electronic book); an imagereproduction device provided with a recording medium (typically, adevice which can reproduce the recording medium such as a DVD (digitalversatile disc) and display images thereof); and the like. Asrepresentative examples of these electronic appliances, a television, apersonal laptop computer, and an image reproduction device provided witha recording medium will be illustrated in FIGS. 10A to 10C.

FIG. 10A is a television including a casing 2001; a supporting base2002; a display portion 2003; a speaker portion 2004; a video inputterminal 2005; and the like. The present invention can be applied to thedisplay portion 2003. The television includes every television fordisplaying information such as one for a personal computer, forreceiving TV broadcasting, and for advertisement. By implementing thepresent invention, a television having a thin and lightweight displayportion can be manufactured.

FIG. 10B is a personal laptop computer including a main body 2201; acasing 2202; a display portion 2203; a keyboard 2204; an externalconnection port 2205; a pointing mouse 2206; and the like. The presentinvention can be applied to the display portion 2203. By implementingthe present invention, a thin and lightweight personal laptop computercan be manufactured.

FIG. 10C is a portable image reproduction device provided with arecording medium (specifically, a DVD player), including a main body2401; a casing 2402; a display portion A 2403; a display portion B 2404;a recording medium (such as a DVD) reading portion 2405; operation keys2406; a speaker portion 2407; and the like. The display portion A 2403mainly displays image information whereas the display portion B 2404mainly displays character information. The present invention can beapplied to both the display portion A 2403 and the display portion B2404. Note that the image reproduction device provided with therecording medium includes a domestic game machine and the like. Byimplementing the present invention, a thin and lightweight portableimage reproduction device equipped with the recording medium can bemanufactured.

What is claimed is:
 1. A method of manufacturing an optical filmcomprising: forming a metal layer on a first substrate; forming aninsulating layer on the metal layer; forming an optical filter on theinsulating layer; attaching a second substrate to the optical filter byusing a first adhesive material so that the second substrate faces thefirst substrate; and separating the first substrate from the opticalfilter in a region between the metal layer and the insulating layer by aphysical means.